std.fmt: breaking API changes

added adapter to AnyWriter and GenericWriter to help bridge the gap
between old and new API

make std.testing.expectFmt work at compile-time

std.fmt no longer has a dependency on std.unicode. Formatted printing
was never properly unicode-aware. Now it no longer pretends to be.

Breakage/deprecations:
* std.fs.File.reader -> std.fs.File.deprecatedReader
* std.fs.File.writer -> std.fs.File.deprecatedWriter
* std.io.GenericReader -> std.io.Reader
* std.io.GenericWriter -> std.io.Writer
* std.io.AnyReader -> std.io.Reader
* std.io.AnyWriter -> std.io.Writer
* std.fmt.format -> std.fmt.deprecatedFormat
* std.fmt.fmtSliceEscapeLower -> std.ascii.hexEscape
* std.fmt.fmtSliceEscapeUpper -> std.ascii.hexEscape
* std.fmt.fmtSliceHexLower -> {x}
* std.fmt.fmtSliceHexUpper -> {X}
* std.fmt.fmtIntSizeDec -> {B}
* std.fmt.fmtIntSizeBin -> {Bi}
* std.fmt.fmtDuration -> {D}
* std.fmt.fmtDurationSigned -> {D}
* {} -> {f} when there is a format method
* format method signature
  - anytype -> *std.io.Writer
  - inferred error set -> error{WriteFailed}
  - options -> (deleted)
* std.fmt.Formatted
  - now takes context type explicitly
  - no fmt string

1 files changed, 1 insertions, 1 deletions

diff --git a/src/Sema/LowerZon.zig b/src/Sema/LowerZon.zig
index 9bd876082f..43c98ebf97 100644
--- a/src/Sema/LowerZon.zig
+++ b/src/Sema/LowerZon.zig
@@ -661,7 +661,7 @@ fn lowerEnum(self: *LowerZon, node: Zoir.Node.Index, res_ty: Type) !InternPool.I
             const field_index = res_ty.enumFieldIndex(field_name_interned, self.sema.pt.zcu) orelse {
                 return self.fail(
                     node,
-                    "enum {} has no member named '{}'",
+                    "enum {f} has no member named '{f}'",
                     .{
                         res_ty.fmt(self.sema.pt),
                         std.zig.fmtId(field_name.get(self.file.zoir.?)),